1. Field of the Invention
The present invention relates to a stroller and more particularly to a lightweight stroller.
The present invention relates to a foldable stroller and, more particularly, to a stroller including components wherein the continued ratio of the distances between the axes of the components is adjusted so that the stroller is formed in a small lightweight structure and excellent in operability, running stability, safety and ride comfort.
2. Description of the Related Art
A known stroller for carrying a baby when a person goes out with the baby for a walk or shopping is foldable when necessary to facilitate storing or carrying the stroller.
FIG. 13 is a partly cutaway perspective view of a stroller having a body structure provided with a base sheet. The body structure of the stroller includes right and left front legs 12 respectively holding front wheels 11, right and left rear legs 14 respectively holding rear wheels 13, a substantially U-shaped handle 15, right and left armrests 16, and right and left connecting rods 17, such as pipes orb the like, extended parallel to each other. End parts of the armrests 16 are pivotally joined to the connecting rods 17, respectively.
Upper end parts of the front legs 12 are pivotally joined to front end parts of the armrests 16, respectively. A curved, bendable guard arm 18 is extended between and detachably attached to the front ends of the armrests 16. Upper end parts of the right and left rear legs 14 are pivotally joined to middle parts of the armrests 16, respectively. Each of brackets 19 having the shape of an inverted letter V has one end pivotally joined to a middle part of the rear leg 14 and a middle part to which a lower end part of the connecting rod 17 is pivotally joined.
A locking part is formed on the other end of each bracket 19. A locking member 20 is mounted on the connecting rod 17. The locking member 20 is slidable along the connecting rod 17. The locking member 20 is engaged with the locking part of the bracket 19 so as to keep the stroller in an unfolded state.
A front stay 22 is provided with a footrest 21 and has opposite ends respectively connected to the right and left front legs 12. A rear stay 23 has opposite ends respectively connected to the right and left rear legs 14. Each of side members 24 has a front end part pivotally joined to a middle part of the front leg 12 and a rear end part pivotally joined to the lower end part of the connecting rod 17 together with both the bracket 19 and a lower end part of the handle 15. A transversely extended upper stay 25 has opposite end parts connected to middle parts of the side members 24, respectively.
The stroller can be maintained in an unfolded state for use by engaging the locking members 20 mounted on the connecting rods 17 with the locking parts of the brackets 19. The locking members 20 can be disengaged from the locking parts of the brackets 19 by operating an operating device 26 mounted on the handle 15. After the locking members 20 have been disengaged from the locking parts of the brackets 19, the stroller can be folded by turning the connecting rods 17 relative to the brackets 19. When the stroller is thus folded in a doubly fold state, the front legs 12 and the rear legs 14 are substantially parallel to each other. The longitudinal dimension of the stroller is reduced by folding the stroller. The stroller in the folded state is suitable for carrying and storage.
The base sheet 27 having a seat plate part 27a and a backrest part 27b is mounted on the body structure of the stroller. The seat plate part 27a of the base sheet 27 is mounted on the upper stay 25. The backrest part 27b has right and left side parts attached to upper parts of the connecting rods 17 extending upward from the joints of the connecting rods 17 and the armrests 16, respectively. When necessary, a baby seat fabricated by sewing, not shown, is mounted on the base sheet 27. A baby is laid in a sitting position or lying position on the baby seat when the stroller is moved.
By the way, the stroller needs to be lifted up, for example, when the person using the stroller goes up stairs. Therefore, weight reduction is one of important problems in designing the stroller.
However, in this known stroller, the side parts of the backrest part 27b of the base sheet 27 are supported on the connecting rods 17 in a hammock manner as mentioned above. As shown in FIG. 13, the right and left side parts of the backrest part 27b are attached to the upper parts of the connecting rods 17 extending upward from the joints of the connecting rods 17 and the armrests 16, respectively. Therefore, the connecting rods 17 are inevitably long and increase the weight of the stroller.
The seat plate part 27a and the backrest part 27b of the base sheet 27 need to be rigid. Therefore, the seat plate part 27a and the backrest part 27b, which are sewn articles, need to be reinforced by core plates, respectively. Therefore, the enhancement of the rigidity of the seat plate part 27a and the backrest part 27b entails increase in weight. A sheet formed by sewing needs to be a bag in order to insert a core plate in the sheet.
The stroller needs to be capable of stably running (running stability), of being easily operated (operability), of safely carrying a baby (safety) and of giving comfortableness (ride comfort) in addition to being small and lightweight. Most strollers in use in those days are unfoldable in an adequate state for carrying a baby and foldable in an adequate state for storage. The stroller is desired to be easily foldable in a small size (facility for folding).
The component members of the foldable stroller are pivotally joined in order to make the stroller foldable. Therefore, the continued ratio of the distances between the turning axes of the component members is determined to insure a folding operation. The foldable construction of the stroller places restrictions on the advance of the miniaturization, operability, running stability, safety and ride comfort of the stroller.